Is physical activity without good sleep enough to prevent cognitive decline?
Authors: Ryan Stanley Falck
Journal: The Lancet Healthy Longevity (2023)

Physical activity and sleep are two lifestyle behaviours that might play a pivotal role in attenuating the effects of aging on cognitive health.1Liu-Ambrose T Falck RS Sleep, physical activity, and cognitive health in older adults.in: Dringenberg HC Handbook of Behavioral Neuroscience. Elsevier, London, UK2019: 665-676Google Scholar Regular physical activity can reduce the risk of dementia by up to 28%,2Hamer M Chida Y Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence.Psychol Med. 2009; 39: 3-11Crossref PubMed Google Scholar while good quality sleep reduces the risk of dementia by 19%.3Shi L Chen S-J Ma M-Y et al.Sleep disturbances increase the risk of dementia: a systematic review and meta-analysis.Sleep Med Rev. 2018; 40: 4-16Crossref PubMed Scopus (376) Google Scholar Physical activity and sleep also share a complex and interdependent relationship by which they affect cognitive health.1Liu-Ambrose T Falck RS Sleep, physical activity, and cognitive health in older adults.in: Dringenberg HC Handbook of Behavioral Neuroscience. Elsevier, London, UK2019: 665-676Google Scholar Most studies examining the interactive relationship of physical activity and sleep with older adult cognitive function are cross-sectional and often with small sample sizes (ie, n <200).4Sewell KR Erickson KI Rainey-Smith SR Peiffer JJ Sohrabi HR Brown BM Relationships between physical activity, sleep and cognitive function: a narrative review.Neurosci Biobehav Rev. 2021; 130: 369-378Crossref PubMed Scopus (14) Google Scholar In a narrative review by Sewell and colleagues,4Sewell KR Erickson KI Rainey-Smith SR Peiffer JJ Sohrabi HR Brown BM Relationships between physical activity, sleep and cognitive function: a narrative review.Neurosci Biobehav Rev. 2021; 130: 369-378Crossref PubMed Scopus (14) Google Scholar the authors found only one longitudinal study5Klaming R Annese J Veltman DJ Comijs HC Episodic memory function is affected by lifestyle factors: a 14-year follow-up study in an elderly population.Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2017; 24: 528-542Crossref PubMed Scopus (0) Google Scholar which investigated the relationships of physical activity and sleep with older adult cognitive function. Importantly, this longitudinal study by Klaming and colleagues5Klaming R Annese J Veltman DJ Comijs HC Episodic memory function is affected by lifestyle factors: a 14-year follow-up study in an elderly population.Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2017; 24: 528-542Crossref PubMed Scopus (0) Google Scholar only examined the independent associations of physical activity and sleep with older adult cognitive performance; whether these behaviours interactively influence older adult cognitive function was unexplored. The study by Mikaela Bloomberg and colleagues6Bloomberg M Brocklebank L Hamer M Steptoe A Joint associations of physical activity and sleep duration with cognitive ageing: longitudinal analysis of an English cohort study.Lancet Healthy Longev. 2023; 4: e345-e353Google Scholar in The Lancet Healthy Longevity is thus an important step forward in our understanding of how physical activity and sleep affect older adult cognitive function. In 8958 cognitively healthy older adults (aged 50–95 years at baseline) from the English Longitudinal Study on Ageing, the authors assessed the independent and interactive associations of self-reported physical activity level (high or low) and sleep duration with cognitive performance at baseline and 10-year follow-up. Participants at baseline with high physical activity who slept 6–8 h/night had better cognitive performance at baseline and 10-year follow-up than people with low physical activity did, irrespective of sleep duration. However, participants at baseline with high physical activity who slept less than 6 h/night declined significantly faster than participants with high physical activity and 6–8 h/night of sleep did, such that their cognitive performance at 10-year follow-up was similar to that of participants with low physical activity. These findings suggest that regular physical activity and healthy sleep are both essential for preventing cognitive decline. Unlike previous cross-sectional analyses which have suggested that physical activity ameliorates the negative consequences of poor sleep on cognitive health,7Lambiase MJ Gabriel KP Kuller LH Matthews KA Sleep and executive function in older women: the moderating effect of physical activity.J Gerontol A Biol Sci Med Sci. 2014; 69: 1170-1176Crossref PubMed Scopus (0) Google Scholar Bloomberg and colleagues' study indicates that poor sleep attenuates the cognitive benefits of physical activity. Thus, the public health message should emphasise the importance of both physical activity and sleep for healthy cognitive ageing. At the very least, suggesting that older adults meet the current 24-h movement guidelines (ie, 7–8 h/night of sleep and ≥150 min/week of physical activity)8Ross R Chaput J-P Giangregorio LM et al.Canadian 24-hour movement guidelines for adults aged 18–64 years and adults aged 65 years or older: an integration of physical activity, sedentary behaviour, and sleep.Appl Physiol Nutr Metab. 2020; 45: S57-102Crossref PubMed Scopus (233) Google Scholar might be important benchmarks for preventing later-life cognitive decline. Several key questions remain unanswered. The findings of this study are based on self-reported physical activity and sleep data, and thus it is important for future research to corroborate these findings using device-based estimates of physical activity and sleep. Second, sleep is a complicated and complex phenomenon, and future investigations need to explore how sleep quality (eg, efficiency) and architecture (eg, slow-wave sleep or rapid eye movement sleep) interact with physical activity to promote healthy cognitive ageing. It is unclear whether the interactive effects of physical activity and sleep on cognitive function are similar across multiple domains of cognition, nor is it clear whether these behaviours jointly affect dementia risk. Finally, we need to understand how social determinants of health (eg, gender, socioeconomic status, race, and ethnicity) might influence the interactive relationship of physical activity and sleep on cognition. In summary, the findings of Bloomberg and colleagues6Bloomberg M Brocklebank L Hamer M Steptoe A Joint associations of physical activity and sleep duration with cognitive ageing: longitudinal analysis of an English cohort study.Lancet Healthy Longev. 2023; 4: e345-e353Google Scholar provide evidence that sufficient physical activity and good sleep are each essential for maintaining cognitive health as adults age. A better understanding of how physical activity and sleep interact with cognitive health will help inform future lifestyle interventions and reduce dementia risk. I declare no competing interests. Funding for this work was provided by a Michael Smith Health Research BC Postdoctoral Fellowship (RT-2021-1639). Joint associations of physical activity and sleep duration with cognitive ageing: longitudinal analysis of an English cohort studyThe baseline cognitive benefit associated with more frequent, higher intensity physical activity was insufficient to ameliorate the more rapid cognitive decline associated with short sleep. Physical activity interventions should also consider sleep habits to maximise benefis of physical activity for long-term cognitive health. Full-Text PDF Open Access